Chemical formula: Al₂O₃

Chemical purity: 3N

Mechanical Properties:

Density g/cc (#/in³): 3.96 (0.14)

Surface Finish - CLA:                                                Micrometers       Microinches 

              As-Fired:                                                           0.5                       20

              Ground:                                                             0.9                       35

              Polished:                                                         <0.03                     <1

Crystal Size:

              Range:                                                              1-6                      39-236

              Average:                                                            3                          118

Water Absorption Percent: 0

Gas Permeability: 0

Color: Ivory

                                                                                   MPa                    psi × 10³

Flexural Strength (Mor) at 20 ^oC:                               552                        80

                                                                                   GPa                     psi × 10⁶

Elastic Modules at 20 ^oC:                                            386                      56

Shear Modules at 20 ^oC:                                             158                       23

Bulk Modules at 20 ^oC:                                                228                       33

                                                                                   m/sec.                  ft/sec.

Trans. Sonic Vel. at 20 ^oC:                                         9.9 × 10³              32 × 10³

Poisson's Ratio at 20 ^oC: 0.22

Stiffness/Weight at 20 ^oC (GPa/g/cc): 97

Fracture Toughness at K_IC (MPA ⋅ m 1/2): 4-5 

                                                                                   MPa                    kpsi

Compressive Strength at 20 ^oC:                                 3792                550

Tensile Strength: at 25 ^oC:                                          310                  45

                      at 1000 ^oC:                                             221                  32

                                                                                   GPa                     kg/mm²

Hardness:           Knoop 1000 g:                                 15.2                   1551

                           Rockwell 45N:                                   90 

 Thermal Properties: 

                                                                                   W/m ^oK              Btu⋅in/ft²⋅h⋅ ^oF

Thermal Conductivity at 20 ^oC:                                      38.9                     270

                                                                                   10^-6/ ^oC               10^-6/ ^oF

Coefficient of Thermal Expansion at 25-1000 ^oC:         8.4                      4.7

                                                                                   J/kg⋅ ^oK              cal/g⋅ ^oC

Specific Heat at 100 ^oC:                                                880                   0.21

                                                                                   ^oC                        ^oF

Thermal Shock Resistance, ΔTc:                                200                 392

Maximum use temperature:                                      1900                3452

Electrical Properties: 

Dielectric Strength:                                           ac-kv/mm           ac-volts/mil

              at 6.35 mm:                                              9.4                       240

              at 3.18 mm:                                             12.8                      325

              at 1.27 mm SPEC:                                    18.1                      460

              at 0.64 mm Thick:                                   23.2                      590

              at 0.25 mm:                                             31.5                      800

                                                                  1 kHz                  1 MHz                 1 GHz

Dielectric Constant at 25 ^oC:                       9.9                     9.8                        --

Dissipation Factor at 25 ^oC:                      0.0020                0.0002                     --

Loss Index at 25 ^oC:                                   0.020                 0.002                      -- 

Volume Resistivity:                                                       ohm-cm²/cm 

               at 25 ^oC:                                                              >10¹⁴

             at 300 ^oC:                                                              >10¹⁴

             at 500 ^oC:                                                            3.3 × 10¹²

             at 700 ^oC:                                                             9.0 × 10⁹

           at 1000 ^oC:                                                             1.1 × 10⁷

                                                                                 ^oC                        ^oF

Te Value:                                                                  1170                 2138

Wear Chemical Properties: 

Corrosion Resistance - Weight Loss:                             mg/cm²/day

              95% H₂SO₄ at 20 ^oC:                                               0.01

             95% H₂SO₄ at 100 ^oC:                                               0.1

Impingement: 0.14

Rubbing: 0.55